Check execution plan

set autotrace on

Execution Plan
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SELECT STATEMENT Optimizer=CHOOSE (Cost=541550 Card=49 Bytes =15092)
0 COUNT (STOPKEY)
1 INLIST ITERATOR
2 TABLE ACCESS (BY INDEX ROWID) OF 'TC_xx_TRADE' (Co st=541550 Card=1462696 Bytes=450510368)
3 INDEX (RANGE SCAN) OF 'IDX_TC_REF_TRA_GMT_XIAOER' (N ON-UNIQUE) (Cost=4475 Card=1462696)

Statistics
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0 recursive calls
0 db block gets
898 consistent gets
0 physical reads
0 redo size
15366 bytes sent via SQL*Net to client
689 bytes received via SQL*Net from client
5 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
49 rows processed

Plan Table:
@$ORACLE_HOME/rdbms/admin/utlxpls.sql